1. Field of the Invention
The present invention relates to a capstan motor, and more particularly to a capstan motor for a magnetic recording and reproducing apparatus, which is provided with a guide portion for guiding and installing other elements on a deck is formed to a bearing holder and a base plate of a stator section for minimizing the deck and improving workability of deck assembly.
2. Description of the Prior Art
In a deck mechanism of a general magnetic recording and reproducing apparatus, as shown in FIG. 1, loading paths 2 and 3 are formed to both sides of a head drum 1, and slant post bases 8 and 9 provided with supply and take-up side slant posts 4 and 5 and guide rollers 6 and 7 are installed to be movable along the loading paths 2 and 3 by means of a separate driving force.
A plurality of guide posts 10A, 10B, 10C and 10D, a tension post 11, a fullwidth erase head 12, an audio/control head 13, a pinch roller 14 and a capstan shaft 15 are installed onto the deck to constitute a travelling system of a tape T.
In the deck mechanism of the above-stated magnetic recording and reproducing apparatus, once a loading signal of tape T is supplied, the slant posts 4 and 5 and guide rollers 6 and 7 of the supply and take-up side slant post bases 8 and 9 draw the tape T to move along loading the paths 2 and 3 to force tape T to wind around the outer circumference of the head drum 1 by as much as approximately 180.degree.. At the same time, the tension post 11 and pinch roller 14 become in contact with the tape T by a predetermined pressure. Under this state, tape T advances forward or backward direction in accordance with the rotational direction of the capstan shaft 15.
Here, the structure of a capstan motor M equipped with the capstan shaft 15 for providing a transferring force to tape T will be described in detail with reference to the accompanying drawings.
As shown in FIG. 2, capstan motor m of the general magnetic recording and reproducing apparatus is classified into a rotor section and a stator section.
In connection with the construction of the rotor section first, a permanent magnet 22 for forming a magnetic field required for the rotation of capstan motor m is adhesively fixed to the lower surface of a rotor case 21. A FG magnet-binding part 23 magnetized by a plurality of N and S polarities is adhesively fixed to the outer periphery of rotor case 21 for detecting a rotative speed. A pulley 24 is fixed to the bottom center of rotor case 21 to be integrally rotated for transferring a power which rotates a reel for supplying or taking up tape T within a tape cassette. Meantime, capstan shaft 15 contacting pinch roller 14 by the predetermined pressure is fixedly fitted into the center of pulley 24. Also, capstan shaft 15 is rotatably supported by a bearing 33 of the stator section which will be described as follows.
In considering the construction of the stator section, an armature winding 32 corresponding to permanent magnet 22 of the rotor section is adhesively fixed to the lower surface of a base plate 31. A bearing holder 34 installed with bearing 33 which rotatably supports capstan shaft 15 is fixed to the upper and lower sides of the center of base plate 31.
An MR device 35 for detecting the rotative speed of capstan motor m is installed to a predetermined portion of the bottom surface of base plate 31 opposite to FG magnet-binding part 23.
The capstan motor m of the general magnetic recording and reproducing apparatus constructed as above is assembled to be installed onto the deck as below. Referring to FIGS. 3 and 4, after a drum base 42 fixed with head drum 1 is fixed to a chassis 41, a loading base 43 formed with loading paths 2 and 3 is fixed to the lower side of drum base 42. Then, capstan motor m is fixed while capstan shaft 15 of capstan motor m projects via a fixing hole 41a in chassis 41, and head drum 1 is put on drum base 42 to be jointly fixed by a typical fixing unit.
On the other hand, one example of a take-up guide apparatus of the magnetic recording and reproducing apparatus applied with the general capstan motor will be described with reference to the drawings.
Referring to FIG. 5, when a loading gear 50 is rotated by the driving of a driving motor (not shown), a middle lever 51 is rotated about a shaft pin 52 counter-clockwise associative with the rotation of loading gear 50. Thus, a lock pin 51a of middle lever 51 pushes one side of a spring 53. By doing so, a pinch arm 54 installed with pinch roller 14 rotates clockwise by the elasticity of spring 53 to tightly press pinch roller 14 onto capstan shaft 15 by the predetermined pressure.
At this time, a lock pin 54a of pinch arm 54 pushes a spring 56 supporting a take-up guide 55 to the rear side, so that take-up guide 55 also rotates clockwise by the pressing force of spring 56, thereby drawing out the tape within the cassette.
A stopper pin 57 which allows take-up guide 55 to rotate until reaching a prescribed position during the clockwise rotation of take-up guide 55 is installed onto chassis 41. Consequently, the rotation of take-up guide 55 beyond the prescribed position is restricted by stopper pin 57.
However, in the above-described capstan motor of the general magnetic recording and reproducing apparatus, bearing holder 34 is fixed to base plate 31 to function for supporting the rotation of capstan shaft 15, and bearing holder 34 and loading base 43 are separately formed.
Therefore, in order to install separately-formed bearing holder 34 and loading base 43 onto chassis 41, a predetermined space on chassis 41 is needed for each element. That is, for installing loading base 43 and bearing holder 34 onto chassis 41 without causing interference against each other, respective elements require respective spaces occupying some area to inevitably make the overall size of the deck bulky which impedes miniaturization of the deck.
In addition, as shown in FIG. 5, the installation interval between stopper pin 57 and take-up guide 55 for the restriction upon the rotational operation of take-up guide 55 is so narrow that the operation of assembling take-up guide 55 to chassis 41 becomes intricate to degrade workability of the assembling operation.